thanks mark for replying.. but i have switched on that wireless button shown in the fig but it still showing "wireless disabled by hardware switch". If i need to install drivers for it pls tell me how to do it? thanks agaun
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krishnaFeb 16 '12 at 13:33

hey good news .. now its working in my laptop " rfkill unblock all " works for me
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krishnaFeb 16 '12 at 16:06

Try shutting down(if not already off), disconnecting the power, remove battery(if it is a laptop), press power a few times to release stored energy, reinsert battery(if it is a laptop), reconnect AC power. Turn on computer. Worked for me. After trying multiple fixes I found on the internet I remembered reading this somewhere. My hardware was blocked via a hardware switch(fn+f8) which doesn't work in ubuntu(works with windows, but uninstalled windows). rfkill showed 0: phy0: Wireless Lan as Hard Blocked.